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Java and security expert with over 10 years of experience with the language and with the practical application of cryptographic protocols - including the design of protocols within international standardization bodies. Creator of a heavily used common criteria certified product. Over 30 years of experience with computers. Likes kids, cats, reading, movies and several sports.


Oct
27
comment OFB or CTR mode without an IV
@poncho Yeah, I know that there are multiple issues with WEP, but I focussed in my answer on the one that was directly related to the repetition of the IV/nonce.
Oct
27
answered OFB or CTR mode without an IV
Oct
21
awarded  Popular Question
Oct
14
revised PBKDF2WithHmacSHA512 Vs. PBKDF2WithHmacSHA1
added 128 characters in body
Oct
14
comment What kind of machine can generate 100-400 digits prime number? RSA
For an example, check out the implementation of the Java BigInteger class; internally it consists of an array of longs, which can easily be seen in any Java debugger.
Oct
14
revised What kind of machine can generate 100-400 digits prime number? RSA
done -> performed
Oct
14
comment Random session key + predictable IV
Using null can be confusing. null is commonly used for references, not for values. A zero valued byte array or just zero IV is more clear.
Oct
14
revised PBKDF2WithHmacSHA512 Vs. PBKDF2WithHmacSHA1
deleted 1 characters in body
Oct
14
answered Is scrypt a hashing function, encryption, or PBKDF?
Oct
14
answered What kind of machine can generate 100-400 digits prime number? RSA
Oct
13
revised PBKDF2WithHmacSHA512 Vs. PBKDF2WithHmacSHA1
edited body
Oct
13
comment PBKDF2WithHmacSHA512 Vs. PBKDF2WithHmacSHA1
I guess you are better off using a binary field instead of hex for the salt, but if you must you should use a CHAR field of 128 bytes, not 64. Furthermore, it may be a good idea to store the iteration count as well or create a "protocol indicator" or version field so you can upgrade your security later on.
Oct
13
answered PBKDF2WithHmacSHA512 Vs. PBKDF2WithHmacSHA1
Oct
12
comment Decrypting the password from SHA-512 hash value
@corsiKa If you use a broken hashing method then anything can happen. But a hashing method must be terribly broken if you can retrieve the original password without reverting to brute force. I don't think we have to mention that the implementation should not be using broken functions for every answer.
Oct
12
accepted Practical disadvantages of GCM mode encryption
Oct
8
comment Dual_EC_DRBG and OpenSSL on a Mac
Anything missing from my answer?
Oct
8
revised Using multiple secret keys
added 161 characters in body
Oct
8
comment AES block cipher modes of operation
A block cipher simply encrypts one block at a time. The block cipher has state, and you cannot reuse that state before you've ended the standardized number of rounds (10 rounds for 128 bit). So you may not be Wright, but you seem to have got the idea.
Oct
6
comment Practical disadvantages of GCM mode encryption
I'm not so impressed with the implementation bug. I found an error in the utility functions of SJCP that completely skipped the AAD for both the signing and verification in CCM mode. Always check your boundaries. It's interesting to read that it would lead to message forgery attacks though. I do agree that GCM spec. does allow for non-sensical tag sizes for sure. It's a bit too flexible in that sense.
Oct
6
comment Is this a good entropy collector and whitening technique?
Personally I have a hard time understanding the behavior in time for the above. If you just want to create the output of the pseudo random number generator, just supply the above entropy as (additional) seed to an existing PRNG.